Thorium Isotope Distributions in the Eastern Equatorial Pacific

  • Michael P. Bacon
  • Robert F. Anderson
Part of the NATO Conference Series book series (NATOCS, volume 9)

Abstract

Measurements of the radiogenic thorium isotopes 234Th 230Th and 228Th in seawater show that all of the isotopes occur mainly in the dissolved form (< 1.0 μm). The fraction of the Th found in the particulate form increases as the radioactive half-life of the isotope increases. We conclude that chemical scavenging of Th in the deep sea occurs by a reversible exchange process and that the rate of exchange is fast compared with the rate of removal of the particulate matter. As a result the suspended particles are nearly equilibrated with the surrounding water with respect to exchange of Th isotopes at their surfaces. This suggests that chemical equilibrium principles may be applicable to the problem of trace metal scavenging in the deep sea.

Keywords

Earth Planet Isotope Distribution Total Suspended Matter Fine Particulate Matter Woods Hole Oceanographic Institution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Bhat, S.G., S. Krishnaswamy, D. Lal, Rama and W.S. Moore, 1969: Th 23/U238ratios in the ocean.Earth Planet. Sci. Lett. 5, 483–491.CrossRefGoogle Scholar
  2. 2.
    Moore, W.S. and W.M. Sackett, 1964: Uranium and thorium series inequilibrium in sea water. J. Geophys. Res. 69, 5401–5405.CrossRefGoogle Scholar
  3. 3.
    Moore, W.S., 1969: Measurement of Ra228 and Th228 in sea water. J. Geophys. Res. 74, 694–704.CrossRefGoogle Scholar
  4. 4.
    Goldberg, E.D., 1954: Marine geochemistry 1. Chemical scavengers of the sea. J. Geol. 62, 249–265.CrossRefGoogle Scholar
  5. 5.
    Goldschmidt, V.M., 1954: Geochemistry. Clarendon Press, Oxford, 730 pp.Google Scholar
  6. 6.
    Krauskopf, K.B., 1956: Factors controlling the concentration of thirteen rare metals in sea water. Geochim. Cosmochim. Acta. 9, 1–32B.CrossRefGoogle Scholar
  7. 7.
    Turekian, K.K., 1977: The fate of metals in the oceans. Geochim. Cosmochim. Acta. 41, 1139–1144.CrossRefGoogle Scholar
  8. 8.
    Bacon, M.P. and R.F. Anderson, in press: Distribution of thorium isotopes between dissolved and particulate forms in the deep sea. J. Geophys. Res. Google Scholar
  9. 9.
    Spencer, D.W. and P.L. Sachs, 1970: Some aspects of the distribution, chemistry and mineralogy of suspended matter in the Gulf of Maine. Mar. Geol. 9, 117–136.CrossRefGoogle Scholar
  10. 10.
    Krishnaswami, S., D. Lal, B.L.K. Somayajulu, R.F. Weiss and H. Craig, 1976: Large volume in situ filtration of deep Pacific waters: mineralogical and radioisotope studies. Earth Planet. Sci. Lett., 32, 420–429.CrossRefGoogle Scholar
  11. 11.
    Anderson, R.F.: The marine geochemistry of thorium and protactinium, Ph.D. dissertation, Massachusetts Institute of Technology/Woods Hole Oceanographic Institution, WHOI-81–1, 287 pp.Google Scholar
  12. 12.
    Craig, H., S. Krishnaswami and B.L.K. Somayajulu, 1973: 210pb — 226Ra: radioactive disequilibrium in the deep sea. Earth Planet. Sci. Lett. 17, 295–305.CrossRefGoogle Scholar
  13. 13.
    Bacon, M.P. D.W. Spencer and P.G. Brewer, 1976: 210Pb/ 226Ra and 210Po/21 Pb disequilibria in seawater and suspended particulate matter. Earth Planet. Sci. Lett. 32, 277–296.CrossRefGoogle Scholar
  14. 14.
    Schindler, P.W., 1975: Removal of trace metals from the oceans: a zero order model. Thal. Yugoslavica 11, 101–111.Google Scholar
  15. 15.
    Brewer, P.G. and W.M. Hao, 1979: Oceanic elemental scavenging. In: “Chemical Modeling in Aqueous Systems”, E.A. Jenne, ed., ACS Symposium Series, No. 93, pp 261–274, American Chemical Society, Washington, DC.CrossRefGoogle Scholar
  16. 16.
    Balistrieri, L., P.G. Brewer and J.W. Murray, 1981: Scavenging residence times of trace metals and surface chemistry of sinking particles in the deep ocean. Deep-Sea Res. 28A, 101–121.CrossRefGoogle Scholar
  17. 17.
    McCave, I.N., 1975: Vertical flux of particles in the ocean. Deep-Sea Res. 22, 491–502.Google Scholar
  18. 18.
    Lambert, C.E., C. Jehanno, N. Silverberg, J.C. Brun-Cottan and R. Chesselet, 1981: Log-normal distributions of suspended particles in the open ocean. J. Mar. Res. 39, 77–98.Google Scholar
  19. 19.
    Brewer, P.G., Y. Nozaki, D.W. Spencer and A.P. Fleer, 1980: Sediment trap experiments in the deep North Atlantic: isotopic and elemental fluxes. J. Mar. Res. 38, 703–728.Google Scholar
  20. 20.
    Osterberg, C., A.G. Carey, Jr. and H. Curl, Jr., 1963: Acceleration of sinking rates of radionuclides in the ocean. Nature 200, 1276–1277.Google Scholar
  21. 21.
    Cherry, R.D., S.W. Fowler, T.M. Beasley and M. Heyraud, 1975: Polonium-210: its vertical oceanic transport by zoo-plankton metabolic activity. Mar. Chem. 3, 105–110.CrossRefGoogle Scholar
  22. 22.
    Higgo, J.J.W., R.D. Cherry, M. Heyraud and S.W. Fowler, 1977: Rapid removal of plutonium from the oceanic surface layer by zooplankton fecal pellets. Nature 266, 623–624.Google Scholar
  23. 23.
    Beasley, T.M. M. Heyraud, J.J.W. Higgo, R.D. Cherry and S.W. Fowler, 1978: 210 Po and210 Pb in zooplankton fecal pellets. Mar. Biol. 44, 325–328.CrossRefGoogle Scholar
  24. 24.
    Bishop, J.K.B., J.M. Edmond, D.R. Ketten, M.P. Bacon and W.B. Silker, 1977: The chemistry, biology and vertical flux of particulate matter from the upper 400 m of the equatorial Atlantic Ocean. Deep-Sea Res. 24, 511–548.Google Scholar
  25. 25.
    Honjo, S., 1978: Sedimentation of material in the Sargasso Sea at a 5367 m deep station. J. Mar.Res.,36, 469–492.Google Scholar
  26. 26.
    Honjo, S., 1980: Material fluxes and modes of sedimentation in the mesopelagic and bathypelagic zones. J. Mar. Res. 38, 53–97.Google Scholar
  27. 27.
    Deuser, W.G. and E.H. Ross, 1980: Seasonal change in the flux of organic carbon to the deep Sargasso Sea. Nature 283, 364–365.Google Scholar
  28. 28.
    Lal, D., 1980: Comments on some aspects of particulate transport in the oceans. Earth Planet. Sci. Lett. 49, 520–527.CrossRefGoogle Scholar
  29. 29.
    Tsunogai, S. and M. Minagawa, 1978: Settling model for the removal of insoluble chemical elements in seawater. Geochem. J. 12, 47–56.CrossRefGoogle Scholar
  30. 30.
    Moore, W.S., 1981: The thorium isotope content of ocean water. Earth Planet. Sci. Lett. 53, 419–426.CrossRefGoogle Scholar
  31. 31.
    Nozaki, Y., Y. Horibe and H. Tsubota, 1981: The water column distributions of thorium isotopes in the western North Pacific. Earth Planet. Sci. Lett. 54, 203–216.CrossRefGoogle Scholar
  32. 32.
    Nozaki, Y., K.K. Turekian and K. von Damm, 1980: Pb in GEOSECS water profiles from the North Pacific. Earth Planet. Sci. Lett. 49, 393–400.CrossRefGoogle Scholar
  33. 33.
    Bacon, M.P., P.G. Brewer, D.W. Spencer, J.W. Murray and J. Goddard, 1980: Lead-210, polonium-210, manganese and iron in the Cariaco Trench. Deep-Sea Res. 27A, 119–135.CrossRefGoogle Scholar
  34. 34.
    Spencer, D.W., M.P. Bacon and P.G. Brewer, 1981: Models of the distribution of 210Pb in a section across the north equatorial Atlantic Ocean. J. Mar. Res. 39, 119–138.Google Scholar

Copyright information

© Springer Science+Business Media New York 1983

Authors and Affiliations

  • Michael P. Bacon
    • 1
  • Robert F. Anderson
    • 1
  1. 1.Department of ChemistryWoods Hole Oceanographic InstitutionWoods HoleUSA

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